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Physics

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Displaying 851 - 875 of 2516

Optical-Clock-Based Time Scale

October 30, 2019
Author(s)
Jian Yao, Jeffrey A. Sherman, Tara M. Fortier, Andrew D. Ludlow, Holly Leopardi, Thomas E. Parker, William F. McGrew, Scott A. Diddams, Judah Levine
A time scale is a procedure for accurately and continuously marking the passage of time. It is exemplified by coordinated universal time (UTC), and provides the backbone for critical navigation tools such as the global positioning system (GPS). Present

Subharmonic Entrainment of Kerr Breather Solitons

October 25, 2019
Author(s)
Daniel Cole, Scott Papp
We predict subharmonic entrainment of breather-soliton oscillations to a periodic perturbation at the round-trip time TR in Kerr-nonlinear optical resonators; an integer ratio Tb=TR ¼ N ≫ 1 results for breathing period Tb. Rigid entrainment is observed

A stroboscopic approach to trapped-ion quantum information processing with squeezed phonons

October 24, 2019
Author(s)
Wenchao Ge, Brian C. Sawyer, Joseph W. Britton, Kurt Jacobs, Michael Foss-Feig, John Bollinger
In trapped-ion quantum information processing, interactions between spins (qubits) are mediated by collective modes of motion of an ion crystal. While there are many different experimental strategies to design such interactions, they all face both

Biomimetic Approach to Inhibition of Photooxidation in Organic Solar Cells Using Beta-Carotene as an Additive

October 14, 2019
Author(s)
Sebastian Engmann, Vida Turkovic, Michela Prete, Mikkel Bregnhoj, Liana Inasaridze, Dmytro Volyniuk, Filipp Obrezkov, Juozas V. Grazulevicius, Horst G. Rubahn, Pavel Troshin, Peter R. Ogilby, M. Madsen
Recent improvements in the power conversion efficiencies of organic photovoltaic (OPV) cells have highlighted the fact that OPV device lifetimes are now the main bottleneck for further advances of this technology. As such, understanding and controlling

Detecting Sub-GeV Dark Matter with Superconducting Nanowires

October 10, 2019
Author(s)
Varun Verma, Sae Woo Nam, Ilya Charaev, Marco Colangelo, Karl Berggren, Yonit Hochberg
We propose the use of superconducting nanowires as both target and sensor for direct detection of light dark matter. With excellent sensitivity to low-energy deposits on electrons, and demonstrated low dark counts, such devices could be used to probe

Light-Shift Suppression with Novel Variants of Adaptive Ramsey Spectroscopy

October 3, 2019
Author(s)
Moshe Shuker, Juniper Pollock, John Kitching, Elizabeth Donley, Rodolphe Boudot, V. I. Yudin, A. V. Taichenachev
We present a brief review of the rapidly growing field of autobalanced Ramsey spectroscopy followed by a detailed discussion and review of two novel techniques that were developed and tested in our laboratory: displaced frequency-jump Ramsey spectroscopy

Multipath Mitigation from FM-AM Correlation

October 3, 2019
Author(s)
Archita Hati, Craig W. Nelson
Multipath is one of the limiting factors for an accurate outdoor and indoor localization. We proposed an approach that uses a multipath mitigation derived from the undesired frequency-to- amplitude conversion of a frequency modulated (FM) signal

Lattice theory for binding of linear polymers to a solid substrate from polymer melts: II. Influence of van der Waals interactions and chain semi?exibility on molecular binding and adsorption

September 30, 2019
Author(s)
Jack F. Douglas, Jacek Dudowicz, Karl Freed
The Polymeric Langmuir Theory (PLT), developed in Paper I, is employed to investigate the influence of van der Waals interactions and chain rigidity on the thermodynamics of the reversible molecular binding to interfaces in one component polymer fluids

Systematic uncertainty due to background-gas collisions in trapped-ion optical clocks

September 30, 2019
Author(s)
Aaron M. Hankin, Ethan Clements, Huang Yao, Samuel M. Brewer, Jwo-Sy Chen, Chin-wen Chou, David Hume, David Leibrandt
We describe a framework for calculating the frequency shift and uncertainty of trapped-ion optical atomic clocks caused by background-gas collisions, and apply this framework to an 27Al+ quantum-logic clock to enable a total fractional systematic

The Interfacial Zone in Thin Polymer Films and Around Nanoparticles in Polymer Nanocomposites

September 26, 2019
Author(s)
Jack F. Douglas, Wengang Zhang, Hamed Emamy, Fernando Vargas-Lara, Beatriz Betancourt, Francis W. Starr
We perform coarse-grained simulations of model unentangled polymer materials to quantify the range over which interfaces alter the structure and dynamics in the vicinity of the interface. We study both model polymer-nanoparticle (NP) composites with

A Century of WWV: 100th Anniversary Commemoration

September 24, 2019
Author(s)
Glenn K. Nelson
WWV was established as a radio station on October 1, 1919 with the issuance of the call letters by the U.S. Department of Commerce. This paper will observe the upcoming 100th anniversary of that event by exploring the events leading to the founding of WWV

Exceeding the Sauter-Schwinger limit of pair production with a quantum gas

September 21, 2019
Author(s)
Alina M. Pineiro Escalera, Mingwu Lu, Dina Genkina, Ian Spielman
We quantum-simulated particle-antiparticle pair production with a bosonic quantum gas in an optical lattice by emulating the requisite 1d Dirac equation and uniform electric field. We emulated field strengths far in excess of Sauter-Schwinger's limit for

Pumping and decay rates of cold atoms dark states

September 9, 2019
Author(s)
Moshe Shuker, Juniper Pollock, V. I. Yudin, John Kitching, Elizabeth Donley
Coherent dark states in atoms, created by simultaneous interaction of two coherent light fields with an atom, are of prime importance in quantum state manipulation. They are used extensively in quantum sensing and quantum information applications to build

The Interfacial Zone Around Nanoparticles in Polymer Nanocomposites

September 2, 2019
Author(s)
Jack F. Douglas, Beatriz Betancourt, Fernando Vargas-Lara, Francis W. Starr, Wengang Zhang
We perform coarse-grained simulations of model nanoparticles having a diameter on the order of 10 nm in an unentangled polymer matrix in the limit of low nanoparticle concentration to understand how the presence of nanoparticles alter the segmental

Resonant X-ray Emission and Valence-band Lifetime Broadening in LiNO3

August 28, 2019
Author(s)
John T. Vinson, Terrence J. Jach, Matthias Mueller, Rainer Unterumsberger, Burkhard Beckhoff
X-ray absorption and resonant inelastic x-ray scattering measurements are carried out on lithium nitrate LiNO3. Echoing previous studies on ammonium nitrate, the σ orbitals around the nitrogen atoms exhibit a large lifetime effect. Experimentally, this is

A semiclassical theory of phase-space dynamics of interacting bosons

August 21, 2019
Author(s)
Eite Tiesinga, Ranchu Mathew
We study the phase-space representation of dynamics of bosons in the semiclassical regime where the occupation number of the modes is large. To this end, we employ the van Vleck-Gutzwiller propagator to obtain an approximation for the Green’s function of
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